Lubricant compositions containing phosphates of fused ring halo-aromatic compounds

ABSTRACT

Mineral oil lubricating compositions containing organophosphates having at least one fused ring halo-aromatic moiety exhibit improved load-carrying and wear-reducing properties. The haloaromatic moiety must contain at least two aromatic rings and be halogenated on at least one of said rings; preferably it is chlorinated. These lubricating compositions can be used for lubrication of hydraulic systems, internal combustion engines, etc.

United States Patent [191 Metro et al.

Sept. 9, 1975 LUBRICANT COMPOSITIONS CONTAINING PHOSPHATES OF FUSED RING HALO-AROMATIC COMPOUNDS Inventors: Stephen J. Metro, Scotch Plains; Harold Shaub, New Providence, both of N.J.; Frank Tao, Baytown,

Tex.

Assignee: Exxon Research and Engineering Company, Linden, NJ.

Filed: July 15, 1974 Appl. No.: 488,574

Related US. Application Data Continuation-impart of Ser. No. 245,627, April 19, 1972, abandoned.

US. Cl. 252/46.7; 252/49.9; 252/78 Int. Cl. ClOM l/48; CIOM 3/42; ClOM 5/24; ClOM 7/46 Field of Search 252/46.7, 49.9, 78

References Cited UNITED STATES PATENTS 2,656,373 10/1953 Gamrath 252/49.9

Primary Examiner-Delbert E. Gantz Assistant Examiner-I. Vaughn Attorney, Agent, or FirmByron O. Dimmick [5 7] ABSTRACT 9 Claims, No Drawings LUBRICANT COMPOSITIONS CONTAINING PHOSPHATES OF FUSED RING HALO-AROMATIC COMPOUNDS CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 245,627, filed Apr. 19, 1972 and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to lubricating oil compositions exhibiting improved wear-reducing properties. These lubricating compositions contain a major amount of a mineral oil base stock and a minor but wear-reducing amount of a phosphate of a fused ring halo-aromatic compound. I,

2. Description of the Prior Art It is well known that compositions us'ed to lubricate metal parts under heavy load can be improved in their load-carrying or wear-reducing properties by incorporating certain additives into them. Such additives have been variously referred to as load-carrying, wear reducing, anti-wear or extreme pressure (EP) addi tives. However, not all load-carrying or extreme presfused unhalogenatcd aromatic rings have also been used as EP additives. See, for example I J .S. Pat. No. 2.340.331.

Despite the prior art noted above, the progressive de velopment of engines and machines that operate under increasingly severe conditions has prompted a continuing search for even more effective EP additives which can be used to make compositions of still further improved wear-reducing and load-carrying properties. The present invention involves the discovery group of additives and compositions.

of such a H In addition, the compositions of this invention can offer other advantages such as being ashless under con- .ditions of use, for example, in the lubrication of diesel engines. Heretofore, it has been found very difficult to formulate effective lubricating oil compositions for diesel engines which exhibit the desirable property of being'ashl ess, that is, leaving no solid residue upon combustion.

DESCRIPTION OF THE INVENTION The lubricating compositions in this invention comprise a major amount of a mineral oil base stock and a minor; but loadcarrying and wear-reducing amount of certain fused ring halo-aromatic phosphates that have in their ester portion at least one aromatic moiety containing at least two fused rings. The halo-aromatic phosphates have the formula:

wherein Ar is an aromatic moiety containing at least two fused aromatic rings, E, Y and Z are each oxygen or sulfur atoms, X is a halogen atom bonded directly to a carbon atom of said rings, 11 is an integer between I and 4 and R and R are C, to C hydrocarbyl alkyl groups.

Preferably aromatic moieties in the additives of this invention contain 2 to 4 fused aromatic rings and are chlorinated In a more preferred embodiment of this invention, the aromatic moiety contains 2 or 3 fused rings, R and R are C, to C alkyl groups, E, Y and Z are all oxygen and l to 2 chlorine atoms are bonded to the aromatic moiety, The aromatic moiety can also contain substituents such as C, to C hydrocarbyl groups, alkoxyl groups, mercapto groups etc. Thus aromatic moieties such as l-chloro-2(n-decyl) naphthyl, 2-bromo-3,4 di(n-octyl) naphthyl and 2,3-dichloro-4- isopropyl'anthryl moieties can be present in the phosphates of this invention. 7

Illustrative, nonlimiting, examples of the haloaromatic phosphates used in the lubricating oil compositions of this invention include compounds of the following structures:

0 s H II OP SCH3 c1 c1 0 II OP(OC2H5)2 O i C it I 2 5 S64E1 OP \SC H SCH Mixtures of such compounds are also within the dent in any way on the method of preparing the aforescope of this invention. described halo-aromatic phosphates. Consequently.

The halo-aromatic phosphates used in the lubricating halo-aromatic phosphates within the scope of this inoil compositions of this invention can be prepared by 2 ven'tion can be used in lubricating oil compositions remany methods known to those of skill in the art. For exgardless of their source. ample. a hydroxylated halo-aromatic precursor can be 4 reacted with a phosphoric acid, an acid phosphate ester In formulating the lubricating oil compositions of this or a halo-derivative of phosphoric acid ,or acid ester to invention, the halo-aromatic phosphates are added to produce a mono(halo-aromatic) dihydrogen phosphate 25 the oil in wear-reducing and load-carrying amounts or phosphoric acid dihalide which can then be further which range from about 0.05 to about 5 wt. 7:. preferareacted to yield the desired halo-aromatic phosphate. bly about 0.1 to about 2.5 wt. most preferably from e.g.,; I about 0. to about one wt. 7!, based on the amount of C1 C1 PO 0 0 G1 I 1| e optoc ti 2 c Alternatively, the halo-aromatic phosphates used in base stock. (All percentages and parts are by weight in the lubricating oil compositions of this invention can be this disclosure unless otherwise noted). made by reacting an appropriate haloquinone with a t 50 The oils that serve as the base stocks for the lubricattri a|ky1 h hi ing oil compositions of this invention are broadly those 0 II OP(OC H 2 5* c1 See, for example, Ramirez et al.. J. Organic Chemistry termed mineral lubricating oils and are derived from Vol. 33, Jan. 1968, pgs. -24. Typically, such rcacthe refining of petroleum crude oils. Generally, they tions are carried out by maintaining the reactant in an containmolecules having between about and inert solvent. such as benzene. at reflux temperature (6 carbon atoms. Such mineral oils may be of any preunder nitrogen for 12 to 24 hours and then evaporating ferrcd type including those deri ed from ordinary parthe solvent to recover a product which is then recrystalzlffi ic. naphth io r mi ed a e mi eral ude i s by lized from an appropriate solvent. suitable refining methods known to those of skill in the The present invention is not intended to be depenart.

Generally. a mineral oil used in this invention will have a viscosity of 210F. of between 45 and about 90 SUS (Saybolt Universal Seconds) and at 100F. a viscosity of between about 100 and about 1250 SUS.

The viscosity indices of the base oils used in the lubricating oil compositions of this invention generally range between about and about 100 or more. In the case of oils employed in high speed, heavy duty diesel engines. oils of high viscosity indices are often preferred, i.e., of the order of 100 or more. The lubricating oil compositions in this invention can contain in addition to the above-described halo-aromatic phosphates, other conventional additives, such as pour point depressants, secondary anti-wear agents, antioxidants, metal deactivators, viscosity index improvers, dyes, dispersants and other such additives well known to those of skill in the art.

In one embodiment of this invention, it is possible to prepare concentrates in which the concentration of the halo-aromatic phosphate is greater than that which would normally be employed in a finished lubricating composition. These concentrates can contain in the range from to 80% of halo-aromatic phosphate on an active ingredient basis, the balance being a hydrocarbon solvent, such as, for example, a mineral oil. Such concentrates are convenient for handling the haloaromatic phosphates in blending operations leading to the finished lubricating oil composition. These concentrates may contain only the halo-aromatic phosphates of the present invention and a suitable mineral oil solvent-diluent or they may also contain other additives such as those described above.

The invention can be more fully understood by reference to the following nonlimiting examples.

EXAMPLE 1 Preparation of 2,3-dichloro-4-methoxy-l-hydroxy naphthalene l-dimethyl phosphate.

The method of Ramirez et al, J. Organic Chemistry, Vol. 33, No. 1, Jan., 1968, pgs. 24, was followed. Commercial 2,3dichloro 1,4-naphthoquinone 100 grams) was recrystallized from one liter of acetone. The recrystallized naphthoquinone 17 grams) was added to a flask with 16 ml. of trimethyl phosphite and 200 milliliters of benzene. The mixture was refluxed for 20 hours under a nitrogen atmosphere and then stripped of excess phosphite and benzene at a pressure of 1.5 millimeters of mercury and a temperature of about 50C. The yellow oil obtained was redissolved in 200 milliliters of benzene. This solution was washed three times with 50 milliliter portions of 5'72 aqueous sodium hydroxide solution and then five times with 50 milliliters of water at which point the wash water had a pH of 7. The benzene solution was then dried over anhydrous magnesium sulfate, the sulfate removed by filtration and the benzene solvent distilled off at a pressure of 160 millimeters of mercury until a pot temperature of 75C. was reached. The residue was triturated three times with 100 milliliter portions of boiling hexane and the hexane portions were combined and stored in a cold box at approximately 50F. for approximately 2 days. Thirteen grams of crystalline crude product was recovered by filtration. These crystals were yellowishwhite in color and had a melting point of 52 to 53C. (reported melting point 5354C.).

EXAMPLE 2 (Evaluation, including comparative tests) The additive of Example 1 was evaluated in two base oils. The first oil used for evaluation, Oil A, was a National Formulary grade White oil having a viscosity at 100F. of 72 SUS, and at 210F. of 37 SUS, and a pour point of 40F., a flash point (COC) of 340F. and a specific gravity at 77F. of 0.834. Oil B was a SAE grade 30 oil designed for use in gas engines, and had a viscosity at 210F. of 59.2 SUS, a viscosity at 100F. of 528 SUS, and a viscosity index of 66.5. Oil B also contained volume percent of an ashless dispersant inhibitor based on the reaction product of one part of tetraethylene pentamine with 2.77 parts of polyisobutenyl propionic acid. The production of such dispersants is disclosed in US. Pat. No. 3,364,130.

To evaluate the load-carrying and wear-reducing properties of lubricant formulations of this invention, these formulations were tested using a four-ball testing device which was essentially the same as the wellknown Shell four-ball wear or extreme pressure testing machine except that the balls were loaded hydraulically rather than mechanically. The machine was equipped with a transducer to provide constant measurement of friction forces.

Briefly, the four-ball test is conducted as follows. The lubricant being tested is placed in the cup of the machine at room temperature. This cup also contains three steel balls of uniform size and composition, fixed in position within the cup. A fourthsteel ball of the same size and composition is held in a chuck above the other three balls and pressed down against them with a known force and rotated at a selected speed for a selected period of time. Successive runs are made with higher loadsuntil failure of the lubricant film is determined, a new set of balls being used for each run. To measure wear rather than extreme pressure properties. wear scar diameters are measured using a load below one that causes film failure.

Lubricant compositions were evaluated in the fourball machine using balls made of Grade 52100 steel in a water-saturated air atmosphere at a temperature between and 80F. Increasingly higher loads (as mea sured in kilograms force) were placed on the balls until seizure occurred, the machine being run at 1200 RPM for 15 minutes at each load level. Seizure occurred when the friction forces became sufficiently great to stop the machine. The seizure load of a lubricant composition is a measure of its load carrying ability.

In order to demonstrate the improvements obtained with lubricating oil compositions of this invention, several similar prior art additives were used in lubricating oil formulations withbase oil A described above and the compositions were tested for purpose of comparison. The same four-ball machine and conditions described above were used to evaluate these control lubricant formulations. With one exception, the control formulations were prepared from commerically available compounds of at least technical grade purity. One prior art compound, octadecyl phenyl chloro-alphanaphthyl phosphate was not available commercially. Accordingly that compound was prepared using the procedure of Example XIII of US. Pat. No. 2,656,373 by reaction of 76.7 grams of POCl with 135.5 grams of l-octadecanol, the product of that reaction then being reacted with the product of reacting 49.4 grams TABLE 1 4-Ball Extreme Pressure Tests Additive Kg Load at Seizure Additive of Invention 120* (Example I Trieresyl phosphate 70 Triphenyl phosphate 60 Trichlorophoyl phosphate '75 ()etadecyl phenyl chloro- 75 alpha naphthyl phosphate *Highest load applied in the test. Sci/are had not occurred at this load. Note: liach composition contained 0.25 wt. '/2 ol' the additive mentioned.

As can be seen from the data of Table I, seizure occurred at from 60 to 75 kg load with each of the prior art additives, whereas with the additive of the present invention seizure had not occurred even at 120 kg load, which was the highest load applied in the test. Thus the additive of this invention was at least l .6 times as effec tive as an extreme pressure additive as any of the prior art additives.

The additive of Example 1 was also blended in 0.25 wt. 71 concentration in Oil B, described above, and the blend wassubjccted to the same extreme pressure test described above. In addition the wear properties of the oil blend were measured on the 4-ball machine by applying a load of 30 kg, representing mild loading conditions, and determining the wear scar diameters on the three lower balls after minutes of running at 1200 RPM. Wear was determined as the average of the wear scar diameters of the three balls. Both the wear proper ties and the extreme pressure properties of base oil B were measured in the same manner. The results appear in Table 11, which follows.

When Oil B was used alone, the machine seized at a load of 60 Kg. 1n contrast, when 0.25% of the additive of Example 1 was added to Oil B, no seizure was obtained, even when the load reached 105 kg. The wear scar diameter obtained with Oil B alone under mild loading conditions Kg load) was 0.46 millimeter while the composition containing 0.25% of the additive of Example 1 gave a wear sear diameter of 0.34 millimeter at 30 kg load. These results demonstrate that the lubricant compositions of this invention have improved load carrying and wear reducing properties.

What is claimed is:

l. A lubricating composition comprising a major amount of a mineral lubricating oil and a minor, load improving amount of a halo-aromatic phosphate of the formula wherein Ar is an aromatic moiety group containing at least 2 fused aromatic rings; E, Y and Z are each oxygen or sulfur atoms; X is a halogen atom bonded directly to a carbon atom of said rings; 11 is an integer between 1 and 4-, and R and R are each C to C alkyl groups.

2. The composition claimed in claim 1 wherein X is i 5. The composition claimed in claim 1 wherein n is 6. The composition claimed in claim 1 wherein Ar contains two fused aromatic rings and 10 to 16 carbon atoms.

7. The composition claimed in claim 1 wherein the haloaryl phosphate has the formula wherein R is a C to C.; hydrocarbyl group.

8. The composition claimed in claim 7 wherein R. R and R are methyl groups.

9. Thecomposition claimed in claim 6 wherein the mineral oil has a viscosity between about and 1250 SUS at 100F. 

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL AND A MINOR, LOAD IMPROVING AMOUNT OF A HALO-AROMATIC PHOSPHATE OF THE FORMULA
 2. The composition claimed in claim 1 wherein X is a chlorine atom.
 3. The composition claimed in claim 1 wherein E, Y and Z are oxygen atoms.
 4. The composition claimed in claim 1 wherein the halo-aromatic phosphate is present in the amount of about 0.05 to 5.0 parts by weight per 100 parts by weight of said oil.
 5. The composition claimed in claim 1 wherein n is 1 or
 2. 6. The composition claimed in claim 1 wherein Ar contains two fused aromatic rings and 10 to 16 carbon atoms.
 7. The composition claimed in claim 1 wherein the haloaryl phosphate has the formula
 8. The composition claimed in claim 7 wherein R, R1 and R2 are methyl groups.
 9. The composition claimed in claim 6 wherein the mineral oil has a viscosity between about 100 and 1250 SUS at 100*F. 